Audio Research VSi60 integrated amplifier

I'm a basically a tube guy, but I've never warmed up to most lower-powered integrated tube amps. Although I quite enjoyed the time I spent with the Cayin A-50T, which I reviewed in the March 2008 issue of Stereophile, over the years I've typically found I'd rather spend time with mid-priced, solid-state integrateds from Creek, Musical Fidelity, or Simaudio than deal with the loss of definition at the frequency extremes that I've heard from many lower-powered tube models. So it was with a bit of trepidation that I approached the VSi60, a 50Wpc integrated amplifier from Audio Research Corporation.

I'd heard good things about the VSi60 from those who'd heard it at the 2009 Consumer Electronics Show, and its tube complement suggested that it might share some technology trickled down from my beloved reference power amplifier, ARC's own Reference 110, which I reviewed in August 2007. Finally, the VSi60's price of $3995 plugged the wide gap between the several fine solid-state integrateds available for $2000–$3000 and the combos of tubed preamps and power amp(s) that begin at about $10,000.

Design
In the VSi60, a passive line stage is combined with a JFET input stage driving two 6H30 driver tubes, one per channel. The output stage for each channel uses a matched pair of Svetlana 6550C push-pull output tubes with a combination of pentode operation and ARC's "partially cathode-coupled topology." The VSi60's circuitry is essentially identical to that of ARC's VS60 power amp ($3495), but with a higher input sensitivity so as to be able to be directly driven by line-level sources. The controls on the faceplate (available in silver or black) are very similar to those on ARC's SP17 preamp. There are six soft-touch buttons (duplicated on the slim, elegant remote control), for Power, Mute, Stereo/Mono, Input selection, and Volume Up/Down.

On the rear panel are five pairs of single-ended inputs labeled CD, Tuner, Video, SE1, and SE2, as well as a full-range mono subwoofer output. Output taps at 4 and 8 ohms are supplied, as well as four pairs of voltmeter test points for setting output tube bias. (ARC claims that biasing the VSi60 is not very tweaky; it should drift only rarely from its factory settings.)

The VSi60 is convenient to use. To warm up the tubes, it automatically mutes itself for the first 30 seconds following turn-on, and a microprocessor remembers the last input and Stereo/Mono settings selected when the unit was powered down. To avoid any accidents, you then have to manually unMute the VSi60 after turn-on before you can do any listening.

A black tube cage is available (add $500). I requested one—amps here live at the curiosity level of my two dogs, and I was concerned that one or both of them might develop Seared Sheltie Snout—but ended up not using it. My dogs were uninterested in the VSi60 (they must be solid-state fans), and installing the cage requires removing the VSi60's sexy-looking, silver-anodized top plate with its recessed Audio Research logo (to provide adequate ventilation). I also thought the cage was butt-ugly. I liked the look of the naked VSi60, in a retro, early-1970s, Audio Research SP3 kind of way.

Warren Gehl, ARC's materials engineer, quality-control technician, and chief "listener," admitted to me that the VSi60 and Reference 110 have many similarities. Each has a JFET input stage and uses the same tube types (although the 110 has twice as many of each). The Reference 110 is, however, a fully balanced design (the VSi60 is single-ended) with much larger power transformers, as well as more exotic and expensive coupling capacitors. Gehl also admitted that, apart from the cost issue, using the Ref 110's larger coupling capacitors in the VSi60 would have resulted in the integrated's physical footprint being larger than ARC wanted.

About that 50Wpc power rating: ARC claims that the VSi60 is designed to drive power-hungry, low-impedance speakers. In fact, Gehl told me, the amp was designed using Wilson Audio Specialties' MAXX IIs, and claims that it can drive them to satisfyingly loud levels in ARC's 32' by 28' listening room. I hooked up the VSi60 to my Alón Circe floorstanders, a very benign 8 ohm load. In fact, in the past I've driven the Circes to satisfyingly loud volumes using single-ended-triode tube amps rated to deliver watts in the single digits.

Sound
The rich, glorious, uncolored, holographic midrange of the VSi60 made it a natural match for well-recorded voices. My favorite John Lennon vocal is in the Beatles' cover of Arthur Alexander's "Anna," from the impeccably remastered The Beatles in Mono (CD, Apple 5 099969945120), and the ARC reproduced it with a delicate yet forcefully dynamic grit, clearly delineating every touch of studio reverb in a bath of guttural glory. In the soprano range, Aretha Franklin's rendering of "Mary Don't You Weep," from her Amazing Grace (CD, Atlantic 2-906-2), was reproduced with her voice blooming within the sort of subtle, linear, powerful dynamic envelope I've heard only from much more expensive tube electronics.

COMPANY INFO
Audio Research Corporation
3900 Annapolis Lane N.
Plymouth, MN 55447-5447
(763) 577-9700
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COMMENTS
Nightspore68's picture

My VSi60 exploded too, twice now. Once at home, then once back at the shop AFTER they had replaced the tubes and protective resistor. I also saw the floor sample VSi60 have an explosion before I bought mine. That makes four explosions, including Stereophile's review sample.
The amp sounds great, but I'll be considering solid state next time.

artofnoise's picture

"The amplifier exceeds that specification from the 8 ohm tap into 8 ohms, with 53Wpc available (17.25dBW) at 1% THD, though only 44W (13.4dBW) were available from the 4 ohm tap into 4 ohms at 1% THD."

13.4dBW is 22 Watts not 44W.

This amp sounds great, what a shame it is prone to self destruction :-)

John Atkinson's picture

John Atkinson wrote:
artofnoise wrote:
only 44W (13.4dBW) were available from the 4 ohm tap into 4 ohms at 1% THD.

13.4dBW is 22 Watts not 44W.

My dBW ratings follow the convention established by Martin Colloms and the late Peter W. Mitchell in the 1980s: they are referred to 2.83V (1W into 8 ohms). Thus 44W into 8 ohms is is 16.4dBW, 44W into 4 ohms is 13.4dBW. An amplifier that behaves as a perfect voltage source (the ideal) thus offers the same dBW rating into all loads, an easy paradigm to grasp.

John Atkinson

Editor, Stereophile

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